Several attempts have been made in the art to reduce the discomfort and irritation resulting from shaving while still allowing for a close shave, i.e. leaving a hair stub as short as possible, preferably having the remaining hair shaft tip rest inside the hair follicle, so that the shaved skin is smooth to the touch.
Multiple blade cartridges, fixed to, or pivot about their handle, such as Gillette brand Sensor Excel™ series, employ the hair pulling-and-cutting process. The process includes a set of “resiliently mounted elements” such as that described in U.S. Pat. No. 5,802,721 or a blade which lifts the hair up, pulling it as far out of the skin follicle as possible, so that the cutting operation is performed by a succeeding blade on the part of the hair that is, when relaxed, below the surface of the skin. This process may sometimes be associated with discomfort resulting from the stiffness of the hairs and the tugging applied to the hair shaft that is strongly attached to the follicle in which it is situated.
In an attempt to minimize the discomfort resulting from the pulling and cutting process, it has become common practice to heat the razor blades and/or facial skin with hot water so as to soften the hair bristles. Shaving creams, gels and lotions have also been developed for the same reason.
Some shaving devices known in the art set out to reduce the discomfort of pulling-on and cutting stiff hairs by heating the device itself. The idea shared by most is heating the cartridge blades employing means other than rinsing with hot water. United States patent application 2006/0117568 describes pre-heating of the razor cartridge prior to shaving and relying on heat conduction to warm the blades. Other shaving devices, such as that described in U.S. Pat. No. 6,836,966 and U.S. Pat. No. 6,817,101, electrically heat the blades themselves in an attempt to soften the hair shafts.